that of Mycetes. Nevertheless Professor "Weldon1 has found in
a female of C. gigot a patch of ossification on the thyroid cartilage
of the larynx which may be an indication of something more in
the male. There are eleven species.
NyctipitKecus, the Doroucouli Monkeys, is a genus of some-
what Lemuriiie appearance, caused by their large eyes. But they
reminded Bates of an Owl or a Tiger-cat! They have a long, but
not prehensile tail. As in the Marmosets, the lower incisors
project forwards in a Lemurine fashion. The thumb is very
short. A peculiarity of this genus is the twenty-two dorso-
lumbar vertebrae. As in Chrysothrix, but not as in Callithrix,
the hemispheres of the brain are smooth. There are five species,
of which one occurs so far north as Nicaragua; the rest are
Brazilian, extending down to the Argentine.
The Ouakari Monkeys, BrcwTiyurus? are, as the name denotes,
short-tailed forms. Two species, B. rubicundus and B. calvus,
Fia. 266.óRed-faced Onakari. Braahyurua r*itncund<u$. x £.
have bright red faces; JR. melanoc&pTicd-us has a black one.
There is a small thumb. The brain is fairly convoluted, and is
to be specially compared with that of Cebv* and Pifliccia. The
1 "Hotes on Cattithrix gigot," Proc. Zool. Soc. 1884, p. 6.
a Forbes, Proc. Zool. &oc. 188O, p. 639.